fix: reverse ordering of calls

[zeynepcaliskan]

Update the calls UI and keyboard index mapping so that newly created calls appear at the top of the list and are assigned the lowest numeric shortcut (1, 2, 3, …). This is done by reversing the iteration order of calls both when building callIndexMap and when rendering ProductionLines.

[birme]

Reviewed as part of a backlog housekeeping pass. The change itself is small and self-contained (reversing call display order in calls-page.tsx and production-lines.tsx), and the checks that ran are green — but the branch is currently conflicting with main (mergeStateStatus: DIRTY), so it can't be merged as-is. Could you rebase onto the latest main and resolve the conflict? Once it's mergeable we can complete the review and merge. Flagging for author attention.

[birme]

Flagged by daily-backlog-pr Phase 3.5 housekeeping: this PR has merge conflicts with the base branch (mergeable=CONFLICTING). It needs a rebase / conflict resolution from the author before it can be reviewed for merge. Not auto-handling since resolving conflicts requires author intent.